The Divine Slayer
by LivLivWatchAnime
Summary: What if someone new came to the High School DxD universe? Would everything change? I mean, how can 1 person change the world? Right? OOC Natsu, OP Natsu, Badass Natsu. And probable harem.
1. The Appearance

_**By:**_ _ **LivLuvWatchAnime**_

"Normal speech"

' _Inner thought'_

 **Spells**

*Sound!*

~Places & Times~

 **Note: Rated M for explicit language, violence, and crude/sexual references.**

 **I welcome constructive criticism. But please try and keep the hate to a minimum. Thanks, as it is expected and appreciated! (MJR reference)**

 **This story was inspired by a bunch of different aspects of OP Natsu stories incorporated/tweaked with my own ideas. However, Natsu is going to be VERY OOC. It's going to be a crossover with Highschool DxD (1 of the funniest animes I've ever seen.) If you like mine, you should check out other ones like the ones 'Natsu is Awesome' helps out with! Without further ado!**

 **I do NOT own Fairy Tail or Highschool DxD!**

 ** _The Divine Slayer_**

* * *

The Appearance

It was a wonderful evening in the peaceful city of Japan where the Occult Research Club was located at Kuoh Academy. It was silent, not a single noise could be heard. Rias Gremory, the next head of the Gremory clan, was enjoying some tea with her queen Akeno Himejima until something grabbed her attention… It was the smell of charcoal.

*BOOM*

Rias instantly shot off the sofa fully alert and looking for what just occurred. When she looked out the window her eyes widened. It looked like a meteor of some sort had just hit Earth? However, that theory was short livid due to the sensation of magical energy resonating from said impact.

"Akeno, let's get going."

Her queen just nodded in understanding as a circle of crimson appeared on the floor beneath them with intricate symbols and patterns on it. The same circle then ascended from the floor around the girls consuming them. When the circle reached above their heads it dissipated and left no trace of them.

* * *

Taking precautions, Rias teleported 500 meters away from the point of collision. Both girls were very attentive to their surroundings, keeping an eye out for any invading objects or organisms. When they arrived at the crash site the smoke was still clearing, and even then the girls could still feel the intense heat from the impact.

Silence. That's all they heard while the 2 young ladies waited patiently for anything to immerge from the smoke, never letting their guards down.

Finally the smoke had begun to disappear into the atmosphere, and as it did, they found out what made the crater. However, it was not what they were expecting.

A young man looking approximately their age was standing there with steam coming off his unscratched skin with an emotionless expression. The 2 things that stood out most to the ladies, was a white scaly scarf wrapped around his neck, and his pink hair.

It took a moment for the information to register for the girls until they looked him over completely. He was wearing a buttoned up one sleeve coat leaving his right arm exposed from shoulder up, white baggy pants that went downs to his knees, and sandals. His eyes, they looked so empty, like he had seen far too much than any man should ever experience.

Rias being the first to finish her observation, asked him "Who are you?" while trying her best to keep a steady glare at him. "…" They received no answer; he only continued to study his environment. Rias, keeping her composure, "Excuse me. But exactly who are you?" She said in a very demanding tone of voice. Right then, for the first time yet, he made eye contact with her. She waited expectantly of an answer.

"You remind me of someone I know." was all the stranger said. Rias being somewhat intrigued continued off of his statement. "And why is that?" She waited a few moments hoping he would respond, however, she was getting impatient. "Did you not he-" She was cut off by him interrupting her "Your hair color, attitude, and your eyes."

She looked at him for a moment confused, _'Hmm, that's strange, I've never heard of someone having my color hair other than members of the Gremory family.'_ Wondering who he was talking about had to ask "And who exactly is this someone?"

His expression immediately took a turn for the worse as his eyes were filled with sorrow and regret. He did not respond; he only looked down with his hair foreshadowing his eyes. Then he made his first movement, he turned around and proceeded to just walk away.

"Hey! We aren't done here yet!" Rias yelled after him. However he just kept on walking almost seemingly like he didn't hear her.

"Stop!" she yelled as she shot a little bit of red magic past his left ear destroying the tree it hit. Surprisingly, the stranger just kept on walking; paying no notice to the danger that it could have caused him.

Akeno, sitting silently for the past few minutes, wasn't too happy that he was disrespecting her king and best friend. Having enough, she brought her arm up, pointing it the sky as clouds had seemed to gather. Then out of nowhere, lightning shot down out of the sky striking where the stranger would've been had he not stopped walking.

"Do I have your attention now?" Rias asked as she gave Akeno a nod with a smile of gratitude for what she did. "…" No response. "Well?" She asked again.

"I will say this once, and once only, so listen well." Said the stranger turning his head so they could see only one eye. However, his eye looked like it was pure red and ready to kill, which in return sent a chill down the girls' spines. "Nothing good ever comes from being near me, if you value your life then you will stay away from me. I only bring chaos, destruction, and death."

He then proceeded to continue walking hoping they would get his message, but something was telling him they wouldn't stop. And sadly, he was right.

"What if I'm used to chaos, destruction, and death?" replied Rias fully used to these occurrences in her daily life.

"No you aren't." He said almost instantly, "You haven't truly seen any of that until you've met me. So I'd suggest you heed my warning."

"And how would you know what I have and haven't seen?" questioned Rias not letting up her argument.

This question however got the stranger to stop once more and turn around completely this time. "Your eyes." He responded surprising her. "All pair of eyes tell a story. Yours are no different. They are identical to hers… before I happened." he said causing his facial expression to sadden.

*Sigh* He looks up at them with the expression they've become accustomed to, emotionless.

"Look, I know I will have to talk to someone at some point." Rias' started to smirk thinking he was going to finally talk. "However. I just cannot do that with you." He said pointing to Rias only.

Taken back by this Rias' eyes widen and asked "Why?" "Because when I look at you, all I see is _her_." He said in a mournful tone. "I will be taking my leave now." He stated. And before Rias or Akeno could retort, a flash of red shone from behind them. Turning around to see what interrupted them, they we shocked to see none other than Rais' older brother, one of the 4 Great Satan himself, Sirzechs. Accompanying him was without a doubt his queen, Grayfia, the 'Strongest Queen'.

"Brother!" Rias shouted still surprised by the fact that he came here in person. "Rias, are you okay?" Sirzechs asked with a tinge of worry in his tone and expression. Rias just nodded in acknowledgment to his question.

Grayfia then cleared her throat in order to remind her master to get the point of there arrival. The Great Satan's expression immediately turning more strict and serious asking "What has happened here Rias?"

Rias, clearing her mind, shot her head back to where the stranger was standing just a few seconds ago; only to find that he was gone…


	2. The Return

_**By:**_ _ **LivLuvWatchAnime**_

"Normal speech"

' _Inner thought'_

 **Spells**

*Sound!*

~Places & Times~

 **Note: Rated M for explicit language, violence, and crude/sexual references.**

 **I welcome constructive criticism. But please try and keep the hate to a minimum. Thanks, as it is expected and appreciated! (MJR reference)**

 **This story was inspired by a bunch of different aspects of OP Natsu stories incorporated/tweaked with my own ideas. However, Natsu is going to be VERY OOC. It's going to be a crossover with Highschool DxD (1 of the funniest animes I've ever seen.) If you like mine, you should check out other ones like the ones 'Natsu is Awesome' helps out with! Without further ado!**

 **Disclaimer:** **I do NOT own Fairy Tail or Highschool DxD!**

The Return

~1 Year since the incident~

"I WILL SAVE YOU RIAS; NO MATTER THE COST!" *Boost!* Issei Hyoudou, the newborn devil and current wielder of the Red Dragon Emperor boosted gear, shouted at the top of his lungs.

Rias Gremory, the next leader of the Gremory clan and fiancé of Riser Phenex, was currently nearing the end of a rating game with none other than each other. It being an arranged marriage, Rias refused to marry a man she does not love and intends on fighting even her family.

That was what she thought was happening, until Issei Hyoudou, her only pawn, collapsed from all the boosts he had done throughout the rating game. "Issei!" she shouted with concern and horror laced in her voice as she saw him cough up blood.

"Haha! All bark and no bite, huh punk?" Riser sneered at seeing Issei lying on the ground helpless. "I'll teach you manners you lowly reincarnated pawn." He scowled as he brought his hands up with flames engulfing them. "You will be burned so badly, that when you teleport out of here, even all the healing won't save you." Riser said with a mischievous and shit-eating grin. "I forfeit." Rias simply stated with no emotion in her voice.

*"Rias Gremory has forfeited the match. The winner is Riser Phenex."* Grayfia's voice rang throughout the entire pocket dimension.

"I'm sorry Rias" Issei muttered before losing consciousness. Then a white light enveloped everything.

* * *

~The Next Day at the Gremory Mansion/Wedding Sight~

All the esteemed guests of the wedding were chatting and some dancing in their handsome suits, and beautiful dresses. All while that was happening Riser Phenex was boasting and bragging to a select few individuals with his shit-eating grin still plastered on his face. Meanwhile, Rias was in her elegant and magnificent white, wedding dress on the upper platform with a sulky and emotionless expression.

"So… You ready to be married Rias?" Sirzechs asked in his nicely tailored tux. "No one can ever be ready to marry someone they do not love." She retorted while her hair covered her eyes. *Sigh* "You know Rias, this is for the be-" Sirzechs started to respond until, yelling from the guards was heard behind the humongous doors to the ballroom. Silence. That's all anybody heard for a few moment, wondering what was happening outside those big doors.

* **BOOM!** *

The next thing everyone knows, the big doors' hinges break from some unknown force and fall down. As the dust starts to clear, everyone watches intently; waiting to see who or what dared to interrupt the big day of the wedding.

The next thing that Rias saw made her eyes bulge out of her sockets; the same pink haired stranger from a year ago, standing there like everything was normal.

"Brother." Rias called out to grab Sirzechs attention. He glanced over to see what he was beckoned for. "It's him." She stated with a serious look in her eyes. The Great Satan immediately knew who she was talking about.

As silence rang over everything, Sirzechs called out "What business do you have here?" in a demanding voice.

The same scaled-scarf fellow just looks around with a nonchalant expression gracing his face.

"Did you not hear me?" Sirzechs questions in an almost threatening manner.

"No, I heard you." Said stranger responded, all the while not even glancing at Sirzechs in the slightest. "And?" The Satan held his ground.

The unknown intruder now singled out his gaze on just the crimson-haired leader. "My business? I have no business here." He responded, not even faltering in the slightest at the tension in the room.

"Then why are you h-" Once again today, Sirzechs was cut off. "I'm here because I cannot condone the event that is about to take place today." Sirzechs just gave him a questioning look as if to continue.

"I met Rias approximately a year ago as you already know. When I first saw her, she instantly reminded me of someone I knew." He continued as if to justify his actions. Sirzechs, still raising an eyebrow about the matter and the stranger's reasons for showing up, signified he must continue.

"The person she reminded me of… I held dear. Every time I look at her, I can only see _her_. As such, I cannot allow her to be married off to someone she does not love, nor even stand." He finished strongly.

"I see." Was Sirzechs only response. Seizing the opportunity, he quickly proposed someone. "How about a wager then?" The stranger, not showing any change in his facial expression allowed him to continue. "A 1v1 duel between you and her fiancé. Winner gets Rias' love."

"Ha! I already proved myself once, why should I do it again?" Riser sneered out loud to everybody. Before Sirzechs could say anything, the stranger answered for him "Pride. If you do not except the challenge then you will be seen not as the legendary Phoenix, but as a chicken."

That for some unknown reason enraged Riser to the point of releasing a bit of magic, just enough to emit a low ray of heat. "You aren't a chicken, are you?" The stranger pressed on. Riser Phenex, now clenching his teeth and fists, shot the stranger a glare and responded "How long do you need? In order to be prepared for your ass whooping; how many days?"

"1/48ths." The stranger responded. "Excuse me?" Riser asked slightly confused. "Sorry, I forgot your tiny bird-brain cannot comprehend 'complex' thoughts. 1/48ths of a day is 30 minutes. Be ready." He retorted before turning around and walking back out through the doorway that he had entered from.

Just as he was about to pass by the doorway, he stopped. Without even turning his head, he said "I do not plan on fighting for Rias to love me, but to allow her to marry who she _truly_ loves. Cause in the end, doesn't everybody deserve at least that? To be with who they love?" As everyone thought about what he said, he continued his advance out the doorway with a solemn look. Not like anybody could see it, but it also held determination along with something else… fire.


	3. The Question

_**By:**_ _ **LivLuvWatchAnime**_

"Normal speech"

' _Inner thought'_

 **Spells**

*Sound!*

~Places & Times~

 **Note: Rated M for explicit language, violence, and crude/sexual references.**

 **I welcome constructive criticism. But please try and keep the hate to a minimum. Thanks, as it is expected and appreciated! (MJR reference)**

 **This story was inspired by a bunch of different aspects of OP Natsu stories incorporated/tweaked with my own ideas. However, Natsu is going to be VERY OOC. It's going to be a crossover with Highschool DxD (1 of the funniest animes I've ever seen). I've decided to give a little shout out to another amazing Natsu fanfic writing: Plasnix112. Great writing and ideas, you should check him out! Without further ado!**

 **Disclaimer:** **I do NOT own Fairy Tail or Highschool DxD!**

The Question

~The Locker Room~

There was a knock on the door to the locker room leading to the stadium. "Come in." was all that was heard from within. As the door swung open, it revealed none other than the beautiful and stunning Rias Gremory in her wedding dress.

The stranger was just sitting down on the bench staring at something in his hand; however, he immediately put it away before she could see what. "So… thank you." She decided to put it as simple as possible. "You have nothing to thank me for. I am only doing what is right." Rias then looked down at her feet in shame, having someone else fight her battle for her; maybe even hurting himself while doing so.

"You don't have to d-" she was cut off abruptly (Seems like he had a tendency to do that to people) by the stranger. "Do you love him?" "No." was all she could say with her eyes being shadowed by her hair. "Do you wish to marry him?" "No." It seemed like it was all she could say for some odd reason. "Then I will stop this atrocity." He stated firmly before getting off of the bench and made his way to the arena entrance.

However, just when he was about to enter the arena he stopped, and without turning his head, "Natsu." He said before continuing his walk outside into the cheering crowd. Just before he disappeared from sight into the blinding crowd, he spoke barely audible "That's my name."

* * *

~The Arena~

As the stranger, now known as Natsu, stopped, facing Riser Phenex from 20 feet away; his facial expression turned deathly serious. "So you didn't wimp out and run, eh?" Riser said in his usual arrogant attitude.

"Tell me, do you run from an ant beneath your feet?" Natsu retorted with a nonchalant response. "Tch." Was all Riser could say, he had this weird feeling of anxiety for some reason.

*"The match between Riser Phenex and…"* Grayfia's announcement was cut short as she just now realized she didn't even know his name. But then, everybody just heard a few whispers from over the announcement channel. *"My apologies, the match between Riser Phenex and Natsu will now began. Start!"*

As the cue to begin was issued, Riser felt his adrenaline begin pumping through his veins. "I believe it's about time you learn who you're messing with ya damn punk!" Riser bellowed as flames started to lick his figure and radiate a little heat that couldn't even be felt due to the protective barrier for the crowd.

From the stadium you could hear some swoons and complements from the Riser Phenex fan girls about how 'hot' he is (no pun intended). "Taste the flames of a phoenix!" Riser shouted while releasing a large torrent of bright gold flames towards Natsu. "Trust me, I will." Natsu whispered very quietly so that no one could hear it.

*BOOM*

An explosion occurred due to the impact of the massive waves of fire hitting its intended target. "Tch. All bark and no bite like the last punk I see." Riser stated with his infamous douche-bag grin.

As he turned around to make his way out of the arena, the announcement came on. "*It looks like the match has been decided, the winner i-*" however, she stopped in her tracks for some odd reason. Everyone looked at each other wondering why she stopped, until they heard it too.

*Sluuuuurp*

All spectators seemed to have a questioning look on their faces wondering what it was… until they saw it. Natsu, the challenger thought to have been beaten, was sucking the flames in and eating them. Riser's jaw had officially dropped to the floor with his eyes wide open.

After Natsu finished eating all the flames, he looked up at the VIP box where Rias, Sirzechs, Lord Phenex, and Grayfia were watching. "Don't just count me out yet." He said solemnly looking directly at Grayfia, the announcer. Grayfia simply nodded… and smiled? Since when did Grayfia ever smile?

That aside, Natsu focused his attention once more on the still surprised heir to the Phenex Clan. Riser, finally regaining his composure spoke "Well, you just got lucky." "Lucky enough to eat flames and come out unscathed? As unlucky as I may be, no one can be just lucky enough to do that."

"Wanna try it again then brat?!" echoed around the arena as Riser lunged forward extending his flame covered fist about to hit Natsu. "No." was all Natsu replied in a low voice. "I will do better." He stated with not even a tinge of doubt in his voice. As soon as he said that, Riser's fist impacts on him… but not in a striking manner; Natsu had caught Riser's fist. Before Riser could even gasp in shock, there was a crunching sound.

"AHHHHHH!"

The immortal devil screamed as Natsu crushed his hand with little to no efforts shown. "Your pride and ego will be your downfall." Natsu whispered in a calm, yet scary tone. But before Riser could reply or retort, **Fire Devil's Crushing Fist!** was shouted from Natsu, as he struck Riser right on his jaw line with a blood-red colored flaming fist. The impact of the fist with Riser's head shot him across the arena in under a second, crashing into the concrete, which was with flying everywhere. "Looks like Phoenixes can fly." was all Natsu said as a result from the spell.

As a minute passed by, the dust finally cleared to show Riser Phenex slowly standing up while holding his jaw line. His entire body was already healed, except for where he had been hit, his jaw.

As Riser opened up his mouth to say something, he was cut off "I'll save you the trouble and pain of answering before you ask." Natsu stated while looking at his jaw. "Your jaw is completely shattered and will take a few months to heal. I thought it'd shut you up for a while."

Once again Riser was cut off by Natsu before he could even speak. "You're wondering what I did in order for your healing to not work, am I correct? Don't answer that, I already know that's what you were gonna ask." He added simply when Riser was about to state his answer. "The magic I used for that hit, **Fire** **Devil Slaying Magic** , magic taught by Fire Devils, to slay Devils."

The entire arena was filled with horror consumed faces and wide eyes; even Sirzechs, the strongest of the 4 Great Satan, widened his eyes at the statement.

Breaking the silence, Natsu, with his face devoid of any emotion, decided to speak "That aside, I will give you 1 chance, and 1 chance only, to correct this situation Riser Phenex." The previous statement grabbing the young devil's attention, Natsu continued "I will ask you a question, tell me a lie or incorrect answer, and you will experience pain that you, nor anybody else, have ever known."

There was silence in the entire arena, not even a whisper could be heard, wondering what the question could be.

"Do you love Rias?"

 **Author's Note:**

 **I've decided to make this into a harem due to that being the only response I've gotten so far. The harem will contain the following girls:**

 **Rias**

 **Akeno**

 **Rossewessei**

 **Serafall**

 **Grayfia**

 **Ophis**

 **(And maybe Raynare)**

 **I don't like having harems so large that they reach double digits or can't even remember everyone, so I'm making this sweet and short.**


	4. The Answer

_**By:**_ _ **LivLuvWatchAnime**_

"Normal speech"

' _Inner thought'_

 **Spells**

*Sound!*

~Places & Times~

 **Note: Rated M for explicit language, violence, and crude/sexual references.**

 **I welcome constructive criticism. But please try and keep the hate to a minimum. Thanks, as it is expected and appreciated! (MJR reference)**

 **This story was inspired by a bunch of different aspects of OP Natsu stories incorporated/tweaked with my own ideas. However, Natsu is going to be VERY OOC. It's going to be a crossover with Highschool DxD (1 of the funniest animes I've ever seen).Without further ado!**

 **Disclaimer:** **I do NOT own Fairy Tail or Highschool DxD!**

The Answer

"Do you love Rias?"

Although the question was sudden, there was an instant reaction from the crowd. "Boo! Of course he loves her!" "You think so low of Lord Phenex, shame on you!"

While the entire audience was letting their answer be known, the heir to the Phenex household stood there, silent and emotionless. "You want to know if I love her?" he asked with a for-once-in-his-lifetime serious look, while Natsu simply nodded in response. Suddenly silence filled the arena as Riser Phenex stood there, weighing his options.

' _So he wants to know if I love her, eh? If I say no, I seem like a bad person, so he must want a yes. However, since he disagrees with this marriage, he might want a no. Hmm.'_

While Riser finished with his thoughts Natsu waited patiently. Rias couldn't help but just stare into his eyes and into the endless reservoir of... nothing? _'How can nothing fill something? His eyes are hollow, yet are filled with incomparable emotion, what on Earth would have to happen in order to get them like that?'_ She couldn't stop thinking about that one comment he had first said when they met a year ago.

* * *

~Flashback: The Forest of Beginnings~

" _What if I'm used to chaos, destruction, and death?" replied Rias fully used to these occurrences in her daily life._

" _No you aren't." He said almost instantly, "You haven't truly seen any of that until you've met me. So I'd suggest you heed my warning."_

" _And how would you know what I have and haven't seen?" questioned Rias not letting up her argument._

 _This question however got him to stop once more and turn around completely this time. "Your eyes." He responded surprising her. "All pair of eyes tell a story. Yours are no different. They are identical to hers… before I happened." he said causing his facial expression to sadden._

~End Flashback~

* * *

Rias grimaced just thinking about how lost in life he looked. Before Rias could continue her trip down memory lane, she heard something that shocked her.

"Yes." Riser Phenex had replied to Natsu's question at last. Natsu's hair foreshadowed his eyes with an unpleasant feeling coming off of him. "You know, I said no lying." He stated calmly with no aggression in his voice… until it happened.

 ***CRACK***

"AHHHHHHHH!"

In under a second Natsu's leg, covered in his Fire Devil Slaying flames, collided with Riser's knee joint, instantly shattering his knee cap and successfully breaking it.

After giving it a minute or two, Riser finally stopped walloping in his pain and looked Natsu in his eyes, void of anything. "I wasn't lying." He stated, trying his best to stand his ground though hopelessly failing." You know, Phoenixes are wise and loyal creatures. They make the best companions… You are no Phoenix, just a brat who got _lucky_ enough to have some of their power; you disgust me."

"Why y-!" Riser was swiftly cut off by Natsu's sudden outburst. "You think you're all that just because you can regenerate? Well I got news for you, no one is invincible!"

Just seconds after Natsu finished, he slammed his combined fists down on Riser successfully knocking him out and demolishing the ground around him resulting in a huge crater.

The air was silent and tense, until Natsu spoke up. "Isn't this what you people love; true strength and sheer power?" The people of the stadium however were silent, not even a single whisper. "Well? Answer me!"he shouted in an attempt for an answer.

Finally he got the answer he was looking for; a brave audience member stood up and shouted in response "Power is everything nowadays! It accomplishes anything! We need it!" Suddenly the entire crowd had gotten up and started cheering and applauding in response for Natsu's display of power. Natsu didn't speak back, all he did was turn around and begin to walk off as if he didn't want to be there.

*"The winner of the duel has been decided. The victor is Natsu!"*

All that could be heard was cheering and screaming from the fans and die hard fighters. As loud as it may have been, Natsu just continued walking, not a care in the world. Seeing this as an opportunity before he left, Rias flew as fast as she could to get to him.

When she landed right behind him, he stopped, but did not turn around. Not wasting any time she quickly started speaking "Natsu! Thank you!" She then ran up to him and hugged him. "Thank you." She whispered with a few happy-filled tears falling from her face.

"You're welcome. However, I have to go now." He replied firmly before detaching her arms from around him and continued to walk forward. "Wait! Will I ever see you again?" she asked in a hopeful tone that showed how fond of him she had grown.

"Sooner than you would think." Was all Natsu said before he disappeared in a pillar of fire…

' _Sooner than I would think? What does he mean by that?'_ Rias thought to herself. _'Oh no, he doesn't mean-.'_ "This is going to be one interesting school year." she chuckled out loud to no one in particular.

 **Author's Note:**

 **I have decided due to a few hopeful fans to include Kuroka and Koneko into the harem. However, I will not be having Koneko in his harem until she embraces her Nekomata powers. And Kuroka won't come into the story until then. But I will include them, they are sisters after all.**

 **However, I would like to know. Should Natsu have his own peerage or just be part of the gang? I won't allow Natsu to be held back by joining Rias' peerage, so that's not an option, but please review and leave a comment so I can do whichever one you guys want!**

 **Sorry for the lack of an update. I've been busy recently with work and vacation, and couldn't find the time and energy to do it. I do try and update as frequently as possible, but I may be busy for this week or so. So sorry if it takes longer. Thanks again for your support, and I hope you enjoyed this chapter! Stay tuned for more next time!**


End file.
